1. Field of the Invention
This invention relates to an electrical conductor terminating system, and more particularly to an electrical conductor terminating system in which electrical apparatus can be installed in the field utilizing either bulk cable on a single or paired-wire quick-connect basis, or connectorized cable on a multiwire plug-in basis, or various combinations of these two wiring methods.
2. Description of the Prior Art
It is standard practice in the installation of certain types of electrical apparatus in the field, such as telecommunications transmission equipment bays in a telephone central office, to interconnect the equipment bays to one another by suitable cabling. This interconnection has been accomplished in a variety of ways, including the use of (1) formed cable, in which interbay cables are preformed in the factory or manufacturing location and then subsequently connected directly to equipment terminals in the field by an installer; (2) bulk cable, in which interbay cables are formed from a bulk cable supply in the field and connected directly to equipment terminals by the installer; (3) connectorized cable, in which equipment local cables are wired to the equipment terminals and provided with connector plugs in the factory, and in which interbay cables also are formed with connector plugs in the factory, with the local cables and the interbay cables subsequently being merely plugged together in the field; and (4) terminal strips having, for example, solderless-wrap or quick-connect terminals, in which the equipment is wired to the terminal strips in the factory, and interbay cables subsequently are formed from a bulk cable supply in the field (as noted hereinabove in method #2) and connected to the terminal strips.
Of the foregoing wiring systems, formed cable (method #1) and bulk cable (method #2) generally are lowest in cost, but require longer installation intervals and extensive activities adjacent to working equipment in the field. These field-wired systems also generally result in lower quality as compared to the factory-wired cables involved in the use of connectorized cables or terminal strips. As between connectorized cable and terminal strips, connectorized cable generally is advantageous because of the short installation interval involved, with the least disruption to existing equipment and services, and because it usually results in the highest overall quality system at the lowest cost. Connectorized cable is also desirable because it facilitates maintenance and relocation or reassociation of equipment. Accordingly, in recent years the use of connectorized cable in the installation of transmission equipment, as well as other types of electrical equipment, has significantly increased. In certain instances, however, connectorized cable is not always practical, as for example where a complex network of transmission equipment bays is to be interconnected. Rather, it then may be preferable to interconnect the equipment bays utilizing bulk cable in association with terminal strips, or to utilize connectorized cable, bulk cable and terminal strips in various combinations with one another.
Heretofore, however, connector plugs for connectorized cable have been designed for use primarily with another mating connector plug, while terminal strips have not been designed for use in combination with connectorized cable. For example, in a connector plug arrangement disclosed in U.S. Pat. No. 3,760,335, issued Sept. 18, 1973 to L. E. Roberts, the wires of two cables which are to be interconnected are secured to quick-connect solderless terminals of respective mating connector housings each having a standard number (e.g., 50) of terminals. After the wires have been connected to the terminals, shields or covers are slid onto the housings over the terminals and the wire portions therein, and the covers and housings are secured together by suitable screws to produce two mating connector plugs. To connect the cables together, the mating connector plugs are then plugged into one another during installation of the equipment in the field. When it is desired to remove, replace or rearrange the connected wires, the covers are disassembled from the housings, and then reassembled thereto when the desired changes have been completed.
Similarly, an example of a known type of terminal strip is disclosed in the U.S. Pat. No. 3,798,587, issued on Mar. 19, 1974 to B. C. Ellis, Jr. et al. . In this patent, one set of wires, such as the wires connected to the terminals of the equipment, are dressed along an elongated insulating block into respective spaced slots in the block. A second elongated insulating block has a row of elongated electrical terminals fixedly mounted therein, with the terminals having quick-connect bifurcated legs at their opposite ends. In use, the bifurcated legs at first ends of the terminals, which project outward from the second insulating block, are connected to the dressed wires in the first insulating block by assembling the two blocks together so that the bifurcated terminal legs receive respective ones of the dressed wires therebetween as the legs are inserted into slots in the first block. A second set of wires, as for example of an interbay cable, then are inserted into respective ones of the bifurcated legs at the other ends of the terminals to establish connections between the two sets of wires. A terminal strip of this same type is also shown in U.S. Pat. No. 3,496,522, issued to B. C. Ellis, Jr. et. al. on Feb. 17, 1970, and U.S. Pat. No. 3,611,264, issued to B. C. Ellis, Jr. on Oct. 5, 1971.
The U.S. Pat. No. 3,878,603, issued to L. A. Jensen on Apr. 22, 1975, discloses a solderless cable splicing device of a type similar to the terminal strip in the above-mentioned U.S. Pat. No. 3,798,587, in which two sets of cable wires to be spliced initially are dressed along an elongated first electrically insulating block and fanned into respective slots between longitudinally spaced wire guide portions on opposite sides of the block. An elongated electrically insulating second block, having a plurality of U-shaped terminals mounted thereon with quick-connect bifurcated legs projecting from the block, then is assembled to the first block with the legs of the terminals receiving respective ones of the fanned wires to complete the splice.
Thus a need exists for a versatile electrical conductor terminating system in which a terminal strip assembly is capable of universal use with various types of cable, such as, bulk formed cable on a quick-connect basis and connectorized cable on a plug-in basis, or various combinations thereof, and the purpose of this invention is to provide such a system which is inexpensive, reliable, capable of accomodating high termination densities, easy to repair and maintain, and readily adaptable to circuit design changes.